1. Field of the Invention
The present invention relates to a transmission control method for controlling the number of access from user terminals to an end server and also relates to a system thereof. In particular, the present invention relates to the transmission control method which estimates the volume of access from user terminals to the end server in advance to control the access from individual user terminals based on the estimated result, thereby controlling the congestion of the end server and also relates to the system thereof.
2. Description of the Related Art
Due to the widespread of mobile terminals with Internet connectivity, sudden surge or increase of access requests caused by special events are becoming a major problem for mobile network carriers/operators. For example, vast volume of access requests could arise during interactive TV programs, such as viewers sending their answers during a quiz show. In addition, these accesses by vast number of viewers tend to concentrate in a short period of time. If such kind of interactive TV programs are provided in a daily basis, the system capacity of the end server, which accepts these requests from the users and provides the interactive TV service, could be used up causing overloads and congestion. And in the worst case, this could result in an operation halt of the server.
In order to solve the above-described technical problems, a technology has been disclosed where an access path server is set in addition to an end server. The access path server decides the access timing of a request from the viewers to the end server. Here, the access timings are calculated based on the server capacity and the prior received volume of access, so that the access sequence of requests are kept in sequential order. The calculated access timing is notified to the user terminals in the form of an access path. User terminals receiving the access path wait and suspend their access until the notified time has elapsed. After suspension, the user terminals are allowed to access the end server.
In the above-described conventional technology, if requests are accepted up to the capacity limit of the end server, accesses can be efficiently processed. However, it is difficult to find the accurate capacity and its surplus of the end server. Therefore, the end server has been generally operated under conditions lower than the capacity limit.
Patent Document 1 has disclosed a technology that controls the access requests from the vast number of viewers by utilizing sample monitoring and dynamic suspension and release of access. Firstly, a part of the viewers generating the access requests are classified into sample and the rest is classified as non-sample. The accesses by sample are allowed to generate freely while the accesses by non-sample are suspended at the terminal. The volume of access by the sample is then monitored and using the monitored volume, the total volume including that of the non-sample is estimated. Control information to release the suspended access of the non-sample is then calculated using the estimated volume and the end server capacity. The calculated control information is advertised to viewers using the broadcasting channel. Consequently, the suspended accesses are released so that the volume after release is controlled near a target value, such as the system capacity. In addition, accesses are released so that the release timings are in sequential order.
Patent Document 1: Japanese Published Unexamined Patent Application No. 2007-48808
In the above-described conventional technology, the access requests by the sample had to be allowed to generate, and hence arrive at the end server, in order to monitor its volume. In addition, access by the non-sample is controlled only after the access by the sample is monitored. Therefore, access by the non-sample had to be temporally suspended until the control information which allows the release of such accesses are received.